Dielectric properties and field-induced phase switching of lead zirconate titanate stannate antiferroelectric thick films on silicon substrates

Thick (similar to 5 mu m) films of antiferroelectric compositions in the lead zirconate titanate stannate family of solid state solutions have been fabricated by sol-gel methods on platinum-buffered silicon substrates. Dielectric properties, electric field induced ferroelectric polarization, and associated elastic strain and the temperature dependence of the dielectric response have been explored as a function of composition. Films with high tin content are shown to undergo a diffuse antiferroelectric-paraelectric phase transition with temperature, probably because of compositional inhomogeneity associated with the high tin content. This type of film also demonstrates a diffuse field-induced antiferroelectric-ferroelectric phase switching under high electric field with the appearance of "slim loop" double hysteresis, which can be attributed to the compositional heterogeneity and the high level of tensile stress in the film because of the thermal mismatch between the film and substrate. On the other hand, the film with high zirconium and low tin content demonstrates a typical antiferroelectric-paraelectric phase change with a sharp peak in dielectric constant on increasing temperature and a typical antiferroelectric-ferroelectric phase switching under high electric field with the appearance of "square loop" double hysteresis. Corresponding to the characteristic of polarization-field hysteresis the film with high tin content possesses a gradual increase of phase switching elastic strain with applied field, reaching a maximum strain level similar to 0.38% and suitable for analogue actuation. The film with high zirconium content possesses a sharp jump of phase switching strain with applied field and reaches a maximum strain level similar to 0.48%, attractive for high strain digital applications. (C) 2000 American Institute of Physics. [S0021-8979(00)04305-X].